[4][5] It is formed by a core of part-time reservists, usually former combat veterans, and in cases of war can be expanded to include local civilian volunteers for local defense, in a case of mass mobilization,[6] with the core expected to lead the mobilized volunteers.

[5] The TDF was officially activated with the start of the 2022 Russian invasion of Ukraine, and more than 100,000 civilians had volunteered by March.

[9] While in the initial stages war in Donbas, the Ukrainian military had a number of setbacks and defeats against the pro-Russian separatist forces, as they were ill-prepared, ill-equipped, lacking in professionalism, morale, fighting spirit and with severe incompetence in the high command.

[25] In accordance with the Constitution and legislation passed by the Supreme Council, the TDF fulfills the following missions: Ukraine's territorial lands is divided into defense zones according to upper-level administrative units (regions, cities of special status, and Autonomous Republic of Crimea), which in turn are subordinate to the relevant operational command of the Armed Forces of Ukraine in whose area of responsibility these administrative units belong.

Approximate staff strength - 423,428 (battalions: 13,284, guard companies: 75,988, defense units: 334,165) service personnel.

Militiamen of the Civil Defence of the TDF, while being paramilitary, are also affiliated to the State Emergency Service of Ukraine.

Because of their territorial defense tasks the Territorial Defense Forces are involved in the Armed Forces of Ukraine and other military formations formed in accordance with the Constitution and laws of Ukraine, including law enforcement forces, units of the State Special Transport Service, State Special Communications Service of Ukraine and the relevant bodies and offices of the government of the republic.

Regional and district military commissariats have a staff defence company, involved in the task of territorial defense (TD).

Preparation of the units of TD held within educational meeting of military service (with practical appeal) and the activities carried out between these.

Units of the ILTD are made up of veterans of foreign armed forces and are organized in like manner as the rest of the TDF.